The invention relates to an apparatus for cleaning soiled films which includes a transport mechanism for the film and a wet cleaning station with a storage chamber for containing liquid cleaning agent for wetting spaced wick plates between which the film passes while being wetted at both sides by the cleaning agent which is drawn into the wick plates from the storage chamber, the wick plates engaging the sides of the film with an adjustable force by means or pressure plates via an intermediate U-shaped band of cloth material.
Such a film cleaning apparatus is disclosed in DE-PS3623452. It facilitates film cleaning while consuming relatively small amounts or cleaning agents because the wick plates extend into the cleaning agent in the storage chamber and transfer the cleaning agent onto the film surface only on the basis or the capillary action of the fleece or felt of which the wick plates consist.
However, during use of this film cleaning apparatus, it became apparent that it is difficult to control the amount of cleaning liquid supplied to the film in such a manner that the film surface is wetted evenly to a minimal degree over an extended period of operation. For supplying the cleaning agent to the film, on one hand, wick plates are required which have good capillary action for transporting the cleaning agent but which, on the other hand, do not carry too much cleaning agent so that the cleaning agent dries off rapidly and evenly from the film surface upon leaving the cleaning station and before coming into contact with the redirecting guide roller. It has been tried so far to control the amount of cleaning fluid admitted to the cleaning area by testing the capillary action of the wick plates and selecting materials which supply the appropriate amount of cleaning agents to the film surface.
It is therefore the object of the present invention to provide a film cleaning apparatus which permits the use of wick plates with very high capillary action, that is, with the capability to transport a large amount of cleaning agent but which, at the same time, offers the possibility to adjust the amount of cleaning agent admitted to the surface of the film in such a way that the cleaning agent supplied by the wick plates to the film per time unit is reduced to the absolutely necessary amount and this amount can be maintained at a constant level.